“…It is interesting to observe that with the increase of incorporation of neem extract, the fiber diameters are increased. These results are less or higher than the results of other literature and in almost all cases in nanofibrous membranes the fiber diameters are more than 100 nm [ 43 , 44 , 45 , 46 ] (see Figures 9 , 10 , 11 ). Figure 7 SEM analysis of the developed nanomembrane sample with 0% neem at different resolutions (a) 50 μm, (b) 30 μm, (c) 20 μm, and (d) 10 μm.…”
“…It is interesting to observe that with the increase of incorporation of neem extract, the fiber diameters are increased. These results are less or higher than the results of other literature and in almost all cases in nanofibrous membranes the fiber diameters are more than 100 nm [ 43 , 44 , 45 , 46 ] (see Figures 9 , 10 , 11 ). Figure 7 SEM analysis of the developed nanomembrane sample with 0% neem at different resolutions (a) 50 μm, (b) 30 μm, (c) 20 μm, and (d) 10 μm.…”
“…More specifically, as the % loading on the filter increased (from 0 to 25%), the contact angle of the water droplet decreased (131−97°), again confirming that the hydrophilic polymeric material P(SSNa24-co-SSAmC 16 -co-GMA20)/PDMAEMA 90/10% (w/w) is present on the HEPA surface. In the graph of Figure 8, the evolution of contact angles is displayed showing that the water droplet is quickly adsorbed on the coated filters, especially in the case of the highest loading (25%), where increased hydrophilicity was observed, with the contact angle reaching the lowest value of 21°after 15 s. This behavior is quite encouraging according to a very recent study, 55 where nanofibrous materials of Znmodified PVDF were prepared for use as air filters. Interestingly, the results of that study indicated that the material with the highest hydrophilicity (high water adsorption) exhibited the highest virucidal activity.…”
Air pollution by pathogens has posed serious concern
on global
health during the last decades, especially since the breakout of the
last pandemic. Therefore, advanced high-efficiency techniques for
air purification are highly on demand. However, in air-filtering devices,
the prevention of secondary pollution that may occur on the filters
remains a challenge. Toward this goal, in the present work, we demonstrate
a facile and eco-friendly process for the biocidal treatment of commercial
high-efficiency particulate air filters. The antibacterial filters
were successfully prepared through spray coating of aqueous solutions
based on biocidal water-soluble polymers, poly(sodium 4-styrene sulfonate-
co
-cetyl trimethylammonium 4-styrene sulfonate-
co
-glycidyl methacrylate) [P(SSNa24-
co
-SSAmC
16
56-
co
-GMA20)] and poly(2-dimethylaminoethyl)methacrylate.
Significantly, an optimized green route was developed for the synthesis
of the used polymers in aqueous conditions and their stabilization
through cross-linking reaction, leading to biocidal air filters with
long-lasting activity. The developed coatings presented strong and
rapid antibacterial activity against
Staphylococcus
aureus
(in 5 min) and
Escherichia coli
(in 15 min). Moreover, the cytotoxicity test of the polymeric materials
toward Α549 lung adenocarcinoma cells indicated very low toxicity
as they did not affect either the cell growth or cell morphology.
The above-mentioned results together with the scalable and easy-to-produce
green methodology suggest that these materials can be promising candidates
as filter coatings for use on air-purification devices.
“…Poly(vinylidene fluoride) (PVDF, average molecular weight ⁓275,000 g mol −1 , Sigma-Aldrich), N,N-dimethylacetamide (DMA, anhydrous, 99.8%, Sigma-Aldrich), AgNO 3 (≥99.9%, Fischer), Cu(NO 3 ) 2 ·2.5H 2 O (≥99.99%, Sigma-Aldrich) and ZnCl 2 (≥98%, Sigma-Aldrich) were used as received from corresponding manufacturers. At first 2 wt% of each salt (AgNO 3 or Cu(NO 3 ) 2 ·2.5H 2 O or ZnCl 2 ) was dissolved in DMA and thereafter 28 wt% of PVDF was added and dissolved at a temperature of 55 °C on a hot plate (IKA C-MAG HS 7) to prepare the spinning solution ( Tõnurist et al, 2009 , 2013a , 2013b , 2014 ; Thomberg et al, 2022 ).…”
Section: Methodsmentioning
confidence: 99%
“…An electrospinning unit with climate control (EC-DIG, IME technologies, Netherlands) holding temperature at 23 ± 1 °C and relative humidity at 60 ± 3% was used for the fabrication of antiviral filter materials as described by Thomberg et al (2022) . Briefly, a plastic syringe (5 ml) was filled with spinning solution and thereafter fitted to a syringe pump (Harvard Apparatus) that enabled to control the solution feed rate.…”
Section: Methodsmentioning
confidence: 99%
“…212695(net) 3 μm). More detailed descriptions and the scheme of the particle filtration efficiency (PFE) testing apparatus can be found elsewhere ( Thomberg et al, 2022 ). In brief, the test aerosol was dryied using a silica gel dryer and two separate instruments were used to measure the particle size.…”
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